nvidia 7 series vs 8 series. (new pc)

What this is actually saying is that, the 7 series does not support directX 10, but that the 7900 card is better for gaming than the 8500 card (and even a bit better/faster than the 8600 card)?

Why am I asking? Well, I'm planning on buying a new pc system 900 euros for the pc, without any perpherals. This is the pc I'm talking about. It seems quite okay, except for the videocard which I probably will have to upgrade to be able to play new games using DirectX 10 (am I correct there?).